Using FSP, the US Navy hopes to save as much as $1.8 million per year in construction costs of high-speed, light-weight ships.

Managing aging fleets of ships is a challenge common to the militaries of several western countries. The benefits of pooling resources to meet common challenges have led to a proliferation of international defense-related organizations. The Technical Cooperation Program (TTCP), for example, cooperates on science and technology for defense applications and is comprised of Australia, Canada, New Zealand, the United Kingdom and the United States.

5,400 kg Ni-Al-Bronze propeller from a Canadian warship

In 2007, Defence Research and Development Canada (DRDC) accessed the Canadian Neutron Beam Centre (CNBC) for a TTCP project toward reducing ship maintenance costs by qualifying a new method of repair – “friction stir processing (FSP)” – for components that are difficult or expensive to remove from the ship, such as propellers. Many ships in western navies use propellers made of nickel aluminum bronze. DRDC researchers studied the effects of FSP on the mechanical and corrosion properties of this material, while a series of experiments over two years at CNBC measured stress and texture. The collective results provided assurance that FSP and its effects on nickel aluminum bronze were sufficiently understood to use FSP for propeller repair. The research team, including representatives of both DRDC and CNBC, was subsequently recognized with a 2008 International Achievement Award by TTCP.

As a result of this research, Canada is revising its specifications and protocols to incorporate the FSP method for propeller repairs. The United States Navy has already adopted FSP and expects to save $400,000 per year in propeller repair costs, and these savings may be just the tip of the iceberg. For example, through continued development of FSP, the US Navy seeks to save as much as $1.8 million per year in construction costs of high-speed, light-weight ships.